1. Field of the Invention
The present invention relates to a zoom lens and an image sensing apparatus using the same and, more particularly, to a zoom lens for forming an optical image on a solid-state image sensing device such as a CCD type image sensor or CMOS type image sensor, and an image sensing apparatus using the same.
2. Description of the Related Art
For compact digital still cameras and video cameras equipped with compact image sensing units comprising solid-state image sensing devices such as CCD (Charge Coupled Device) type image sensors and CMOS (Complementary Metal-Oxide Semiconductor) type image sensors, demands have arisen for zoom lenses having higher imaging performance with an increase in the pixel density of solid-state image sensing devices. In addition, the zoom lenses of compact image sensing apparatuses have been required to be smaller.
As disclosed in, for example, Japanese Unexamined Patent Publication No. 2000-131610 (patent reference 1), there is available a small zoom lens for a compact image sensing apparatus, which is comprised of a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, and a fourth lens group having positive refracting power, and is designed to achieve a reduction in the size of the zoom lens in the thickness direction by placing a prism for bending the optical path in the first lens group.
The zoom lens disclosed in patent reference 1 has, however, a long total length along the optical axis as compared with the focal length, and is not suitable for a compact image sensing apparatus.